The Argentine currency weakened 2.11% to 285 per dollar in the parallel black market following the central bank move, which was announced late on Monday.
According to the measure, soybean exporters selling the oilseed through the so-called "export incentive program," which entails a higher exchange rate, are not allowed to buy foreign currencies starting Tuesday.
Soybean sales during September have a special rate of 200 pesos per dollar as the central bank seeks to boost its own reserves.
Exporters were also blocked from trading foreign currency-denominated securities - even though the measure "does not apply to human beings," the central bank added.
A trader said limiting cash liquidations is set to put pressure on the dollar's black market.
"Nobody wants to hold on to pesos."
In the official market, the Argentine peso was trading down 0.2% at 144.6 per dollar on Tuesday.
(Reporting by Walter Bianchi; Editing by Alistair Bell)
